This invention relates to carriers used in the semi-conductor fabrication industry, and in particular to an apparatus and method of cleaning said carriers.
The process of forming semi-conductor wafers or other delicate electronic components into useful articles require high levels of precision and cleanliness. As these article become increasingly complex and miniaturized, contamination concerns grow. The problems of airborne contamination can be significantly reduced by providing controlled fabrication environments known as clean rooms. While clean rooms effectively remove airborne contaminants found in ambient air, it is often not possible or advisable to completely process wafers in the same clean room environment. Moreover, not all contamination and contaminants are eliminated. For that and other reasons, semi-conductor wafers are transported, stored, and fabricated in bulk with the assistance of protective carriers or pods. These carriers generally include closures which enable the carriers or pods to maintain their own micro-environment. This further reduces the potential from some airborne contaminants.
Contamination and contaminants can generated by other mechanisms. For example, particulates can be generated mechanically by wafers as they are inserted into and removed from wafer carriers, and as doors are attached and removed from the carriers, or they can be generated chemically in reaction to different processing fluids. Contamination can also be the result of out-gassing on the carrier itself, biological in nature due to human activity, or even the result of improper or incomplete washing of the carrier. Contamination can also occur on the exterior of a carrier as the carrier is transported from station to station during processing.
These contaminants and contamination can be reduced by periodically washing and/or cleaning the carriers or pods. Typically, a carrier is cleaned of contaminants and contamination by placing the carrier in a cleaning apparatus which subjects the exterior and interior surfaces to cleaning fluids. Often, the fluids used to clean the exterior surfaces are different from the fluids used to clean the interior surfaces. The expended fluid is usually collected in a common receptacle and discarded. Or a cleaning apparatus will utilize the same cleaning fluids for the exterior and interior surfaces. This allows the expended fluid to be recycled.
There are several problems associated with such carrier cleaners. They use large amounts of material because they do not provide for recycling. With those which do recycle, they are unable to tailor the fluids to the specialized needs of the exterior and interior surface. And they do not provide for door or closure cleaning.
There is a need for a wafer carrier cleaner with minimal cross contamination between exterior and interior surface cleaning fluids, a wafer carrier cleaner which conserves valuable resources, a wafer carrier cleaner with a door cleaning capability, and a wafer carrier cleaner which can operate in a moderately controlled environment.